BGA housings have been known for a relatively long time and are used in the semiconductor industry whenever high connection densities are to be realized on a small space for ICs (integrated circuits).
A typical BGA housing has a housing made of a plastic molding composition on the top side and a carrier or a substrate with solder ball connections on the underside. In the case of a plastic BGA housing (PBGA) the substrate is composed of a plastic material, and the substrate comprises ceramic in the case of a ceramic BGA housing (CBGA). Depending on the BGA type, the solder ball connections are arranged over the whole area or in a plurality of rows. In the interior, the BGA housing has, for example, a conventionally contact-connected IC, a flip-chip or a plurality of semiconductor chips in a stacked design or one beside the other.
Conventional BGA housings have the disadvantage that the heat arising in the semiconductor chip during operation of the semiconductor device can be transported away only poorly. For the purpose of transporting away heat from the semiconductor chip, a conventional BGA housing only affords the option of dissipating the heat into the substrate with the solder ball connections, since the plastic molding composition surrounding the semiconductor chip and the contact-connections typically represents a good thermal insulator.
For those and other reasons, there is a need for the present invention.
In order to improve the dissipation of heat, therefore, substrates are used whose basic body has thermally conductive reinforced copper layers besides the plastic material.
The use of these substrates constructed in layered fashion has the disadvantage that—besides the high costs for a substrate of this type—the dissipation of heat from the semiconductor chip is limited by the thermal conductivity of the joint between the semiconductor chip and the substrate. In the case of BGA housings having a flip-chip in their interior, this thermal conductivity is problematic on account of the dimensioning of the flip-chip contacts.